The present invention refers to a fastening system between two or more parts or elements, in which one of them, taken as a base, acts as the principal support of the system, and as such must be metallic in nature, while the element that is to be fixed must possess a plastic shaft that, inserted in a metallic staple, completes the system. In such a way that the unit is left for its insertion through simple pressure or impact carried out over a window on the metallic base cited beforehand.
The system permits the direct fastening between the two elements previously cited, or either the insertion between them of a panel or the like, of any type of material or nature.
The object of the invention is to obtain an exceedingly fast and secure assembly, with a high grade of stability and great ease for dismantling.
The system may be applied in the furniture industry, in the construction of panelled surfaces, in the manufacturing of home electrical appliances and, particularly for the coating of the interior of automobiles, as well as in any industrial sector where you require similar features.
Fastening systems between two or more parts are already known, systems that use a metallic staple, attachable by pressure, by elastic deformation, in a window that is operatively worked by one of said parts, that must be materialised in a sheet like body, like for example a metallic plate or a panel, being joined to the cited metallic staple a plastic shaft to which is joined, at the same time, to a second part.
Solutions of this type appear reflected in Spanish patent inventions No. 9700865and No. 9700870, as well as Addition Certificates No. 9702231 and No. 9800689, all of which stand in the name of the present applicant.
All these registrations present as a common denominator a problem that is centred fundamentally in two aspects; on the one hand the surface for fastening is relatively small, so that the anchorage can be bettered, and on the other hand it presents dismantling problems, when it is required, which occurs habitually.
The metal-plastic fastening system between parts that the invention proposes resolves in a fully satisfactory manner the problem previously cited in the two aspects stated.
For this, and parting from the basic structure of conventional fastening systems, that is, parting from the existence of a base element, markedly plane, a metallic staple and a plastic shaft defined in the element that is to be fixed, the system of the invention uses a staple obtained by moulding and shaped by means of a metallic sheet, of iron, of a reduced thickness, duly tempered and treated with antirust protection. After the shaping of same, the staple adopts a symmetric configuration with respects to the middle axis, and more concretely through a ridge or common trestle, intermediate and rounded, there are three pairs of flexible tabs. The first pair forming a practically null angle, that is, being the tabs of same approximately parallel, each with creases or brackets that oppose each other in their free and inferior ends. The second pair of tabs forming an angle inferior to 90xc2x0, obtaining the first pair of tabs at the expense of forging the latter, the shafts of the second pair finish off, at their free end, through folds grooved into a xe2x80x9cUxe2x80x9d configuration, oriented outwards and of a considerable longitude. The third pair of tabs are established as a prolongation of the free edge of the intermediate tabs, beyond the respective folds, and with wide lateral expansions that configure four wings. These wings are considerably distanced, whose mission is to adhere through elasticity to all the system at the plane exterior base of the base part, and serving at the same time as a clearing element of an intermediate sheet or panel, when it is necessary.
The first pair of tabs, through their folds or brackets, are designed for the nailing of the plastic shaft participant in the other piece that is to be united, by its middle area. Meanwhile, the folds of the intermediate pair of tabs act by a side as a means of fastening to the borders of the window that is operatively worked in the sheet, and at the same time as a means of lateral fastening for the cited plastic shaft.
In accordance with this structure, the metallic staple is capable of elastically deforming to connect with the sheet, and after said connection it is capable of receiving, also following elastic deformation, the shaft that must be lodged in its interior.
In accordance with the characteristics of the invention, the plastic shaft incorporates an intermediate hollow area through which direct access is established, for example with a screwdriver or the like, to the creases or brackets of the first pair of tabs, in a way that through the rotation of said tool the cited tabs can be deformed elastically, in a separating direction, to liberate the frontal and central zone of the plastic shaft.
On the other hand, after the plastic shaft has become independent, and for the dismantling of the metallic staple, same results easily contractible by means of a pincer movement over the edges defined in the fastening folds of the sheet, through windows operatively carried out on the third set of tabs.
Finally, and in accordance with another of the characteristics of the invention, the plastic shaft is supplied with interior columns between which is defined the cited passage for the screwdriver or tool for the opening of the first pair of tabs. These columns are assisted by exterior reinforcement consoles, that serve at the same time as centering elements in the connection of the shaft, and that may be obtained by termo-plastic injection, a simple opening mould or with movable sides.